Synthesis of [³⁵S]Thiophosphoryl Adenylic Acid, Utilizing a General Procedure for [³⁵S]Thiophosphoryl Chloride Production

Abstract

Elemental [35S]sulfur was shown to equilibrate with the sulfur of thiophosphoryl chloride when these materials are heated together. This isotopic exchange reaction is the basis of a convenient, microscale synthesis of high specific activity [³⁵S]PSCl₃. [³⁵S]Thiophosphoryl chloride is otherwise not commercially available except through custom synthesis. The labeled thiophosphoryl chloride was used in a novel procedure for the preparation of [³⁵S]adenosine 5′-phosphorothioate. This isotopic exchange method should find wide application in the synthesis of many radiolabeled thiophosphoryl esters which utilize PSCl₃ as the source of the thiophosphoryl group.